Magnifying Multifocal Contact Lens Materials
By Rachael A. Wruble, OD, FAAO
Soft multifocal contact lenses have certainly evolved in many facets over the course of the last 20 years. Whereas previous optical designs have seen some limitations, modern multifocal contact lenses offer improved optics in the lenses and various zone designs, which can help serve the visual needs of today’s presbyopes. To that end, newer designs also address the distance and near vision that are needed in several important, routine activities, such as nighttime driving.
Today’s multifocal contact lenses address another critically important signal of wearer satisfaction: comfort. Considering that the estimated average frequency of contact lens dropout is >20%,1 it is important to characterize the relationship between visual acuity and comfort.
Most commonly, dropout can be attributed to discomfort with soft contact lenses. If a presbyope who needs clear, crisp vision consistently throughout the day is also experiencing dryness from their contact lenses, they may very well be at greater risk for blurred vision. Given the change in vision due to discomfort, it’s no surprise that many patients with presbyopes revert to spectacles to obtain the vision that they need.
A Presbyope-Centered Approach
In light of the many different options available today, eye care practitioners (ECPs) must integrate several patient-specific factors in the multifocal contact lens selection process to make appropriate recommendations. An initial assessment by ECPs should consider, at minimum, a patient’s profession, hobbies, and overall lifestyle as potential signals of their visual expectations.
As an example, a truck driver may benefit from a different multifocal contact lens than a patient who spends a considerable amount of time using digital devices. If a patient routinely transitions between multiple digital screens throughout a typical day, they may greatly benefit from a contact lens that maintains a high percentage of moisture. As more and more patients, including presbyopes, increase their computer use as they work from home, the hydration of a lens material is even more of an essential parameter.
Making the Case for Contact Lens Materials
Age-related changes to the ocular surface, including the risk of dry eye disease, are important considerations when working with patients with presbyopia.2 With age, the tear film simply does not function in the same capacity. Changes in tear quality, production, tear breakup time, and the tear meniscus can greatly impact ocular surface homeostasis. As presbyopes seek contact lenses as a form of visual correction, it is essential that ECPs look to fitting them with multifocal contact lenses that can consider these changes and aim to support comfort.
Rigid gas permeable, scleral, hydrogel, and silicone hydrogel lenses are a few examples of materials currently available to presbyopes. Though each material has its advantages, silicone hydrogel contact lenses are differentiated by their porosity and oxygen permeability as a function of maintaining lens hydration. Silicone hydrogel materials also provide value to multifocal contact lens wearers, particularly new wearers, in their favorable handling characteristics.
Owing to its low modulus, silicone hydrogel contact lenses can be easier for initial placement on the finger. Unlike other materials that can feel more delicate, the durability and stability of silicone hydrogel material allows the contact lens to better hold its shape. This feature is advantageous for presbyopes who may already be challenged by tasks at near distances.
Advancements in Material Properties
Many advances in contact lens material technology have made efforts to reduce contact lens discomfort. Dailies Total1 Multifocal contact lenses (delefilcon A), for example, feature Water Gradient Technology that is aimed at improving tear film dynamics by lubricating the outer surface layer.3
Another example of a novel multifocal contact lens system was launched in 2021 using the silicone hydrogel one-day disposable material stenfilcon A (MyDay multifocal with the Binocular Progressive System, CooperVision, Inc, San Ramon, California, USA). This multifocal contact lens system was designed to help presbyopes achieve their vision needs using a unique 3-Add system while delivering ease of fit and high levels of fitting success. Another notable advancement is the Aquaform Technology found in the monthly Biofinity multifocal contact lens (comfilcon A) that uses a fabrication method to make the lens more flexible while minimizing dehydration.
Bausch + Lomb’s INFUSE Multifocal contact lens (kalifilcon A) combines a next-generation silicone hydrogel with ProBalance Technology, which incorporates osmoprotectants, electrolytes, and moisturizers into the lens to help maintain ocular surface homeostasis. Beyond maintaining a balanced homeostatic environment, these additions help multifocal contact lens wearers achieve long-term wear. Of note, the Tear Film and Ocular Surface Society’s (TFOS) Dry Eye Workshop (DEWS) II report called attention to the need for electrolyte balance to avoid hyperosmolarity and maintain ocular surface homeostasis.
Bringing it All Together
Multifocal contact lens satisfaction is strongly tied to both the wearer’s comfort and visual acuity. And though soft contact lens materials and optical design are altogether separate categories, they are both important considerations for ECPs when fitting presbyopes with multifocal contact lenses. The multifocal contact lenses of today address both the visual and comfort needs of presbyopes with material designs that support clear vision at multiple distances, moisture, and ocular surface homeostasis.
Rachael Wruble, OD, is an optometrist and co-owner of Northlake Eye and Belmont Eye who practices at the Belmont, Charlotte, and Concord locations in NC.
References
- Pucker AD, Tichenor AA. A review of contact lens dropout. Clin Optom (Auckl). 2020;12:85-94.
- Lafosse E, Wolffsohn JS, Talens-Estarelles C, García-Lázaro S. Presbyopia and the aging eye: existing refractive approaches and their potential impact on dry eye signs and symptoms. Cont Lens Anterior Eye. 2020;43(2):103-114.
- Fujimoto H, Ochi S, Yamashita T, Inoue Y, Kiryu J. Role of the water gradient structure in inhibiting thin aqueous layer break in silicone hydrogel-soft contact lens. Transl Vis Sci Technol. 2021;10(11):5.
- Lira M, Lourenço C, Silva M, Botelho G. Physicochemical stability of contact lenses materials for biomedical applications. J Optom. 2020;13(2):120-127.
